Fluorescent lamp



Feb. 24, 1942.

FLUORESCENT LAMP Filed April 10, 1941 2 Sheets-Sheet 1 A. HOPKIN, JR 2,273,960

Feb. 24, l 942.

A. HOPKIN, JR

FLUORESCENT LAMP} Filed April 10, 1941 2 Shets-Sheet 2 v gwucnfor,

va30w4u--- hams Feb. 24, .1942

FLUORESCENT LAMP Alfred Hopkin, In, Philadelphia, Pa.

Application April 10, 1941, Serial No. 387,940

3 Claims.

My invention relates to improvements in fluorescent lamps for illuminating purposes.

An important object of the invention is to provide means whereby all terminals for the thermionic electrodes are located at one end'of the lamp.

A further object of the invention is to provide a fluorescent lamp which is of simple construction and may be manufactured relatively cheaply.

A further object of the invention is to provide a fluorescent lamp which may be produced in accordance with the methods generally practiced in producing the ordinary incandescent electric lamp.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings forming a part of this application and in which like numerals are employed .to designate like parts throughout the same:

Figure ,-1 is a side elevation of a fluorescent lamp embodying my invention,

Figure 2 is a central vertical longitudinal section. through the lamp, parts broken away,

Figure 3 15,9. horizontal section taken on line 3-3 of Figure 2,

Figure 4 is a similar view taken on line 4-4 of Figure 2,

Figure 5 is a vertical longitudinal section taken on line 5-5 of'Figure 2, I,

Figure 6 is a similar view showing a modified form of wire connections,

Figure 'I is a side elevation of a fluorescent lamp embodying a modification of the invention,

Figure 8 is a central vertical longitudinal sec-- tion through the lamp, parts broken away,

Figure 9 is a horizontal section taken on line 9-9 of Figure 8,

Figure 10 is a vertical section taken on line lO-IO of Figure 8, and

Figure 11 is a horizontal section taken on line li-Il of Figure 8.

In the drawings, wherein for the purpose of illustration is shown a preferred embodiment of my invention, the numeral Ill designates a preferably cylindrical outer tube formed. of glass or the like and having its inner surface coated with a fluorescent material, as indicated at II. This inner coating preferably extends to or near the points l2.

One end of the tube I0 is covered by a cap l3, formed of glass, and which is brought into conand fused thereto upon -the line H. The cap l3 carries a tubular nipple or support [5, integral therewith. The outer end of this tubular nipple is open while its inner end is'closed by a relatively thick head 16. A tube l1 extends through the tubular nipple I5 and has commu-' nication with the interior of the main tube l0.

The opposite endof the main tube I0 is covered by a glass cap it, arranged in endto-end relation to the main tube lland contacting therewith and fusedto-the same along the line IS. The cap l8 has an inwardly extending tubular nipple 20, having a thick head 2|. The caps and main tube Ill form an air-tight tube, as is obvious. The tube- I1 is employed to evac ate the main tube III, after which mercury an /or a rare gas such as neon, helium, zenon, krypton or argon may be introduced into the main tube l0. Each gas or mercury vapor, or a mixture of the same, constitutes a gaseous atmosphere. The

'numeral .22 designates a globule of mercury.

After the tube i1 is thus used, its outer end is pinched or sealed ofl.

The numeral 23 designates a thermionic electrode, connected across two supporting wires 24,

. which are fused into the head iii. The suptactipg relation with such end of the tube 10 porting wires. 24 are connected with wires 25. Arranged near the opposite end of the main tube I0 is a companion thermionic electrode 26, connected across supporting wires 21, fused in the head 2|. The wires 21 have connection with wires 28, disposed outwardly of the thermionic electrode26 and passing through the main tube ID to the exterior thereof. The wires 28 extend longitudinally of the main tube l0 exteriorly' thereof and these wires are insulated exteriorly of the main tube.

The numeral 29 designates an insulating cap,

formed of Bakelite or the like and this cap is applied to the lower end of the main tube Ill and also receives the cap l3. The outer cap 29 may be secured to the main tube ID by Bakelite" cement 30. The cap 29 has an end 3|, having tubular terminal-plugs 32 embedded therein and the wires 25 pass through these tubular terminalplugs 22 and have their outer ends cut off and soldered to the terminal-plugs, asshown at 32.

The wires 28 pass through grooves 34 and through tubular terminal-plugs 35, embedded in the end 3|. The terminal-plugs 35 have the wires 28 soldered thereto, as shown at 36.

The numeral 31 designates an insulating cap,

formed of Bakelite or the like and this cap is 7 applied to the end of the main tube in and the parts of the lamp,

is of course first 1 trode. The cap I3 is then applied to the end of the main tube It and is fused thereto. The cap l8 has the thermionic electrode 26 mounted thereon and the wires 28 connected with this electrode, and the cap I 8 is now brought into contact with the adjacent end of the main tube It. The wires 28 pass between th adjacent ends of the cap l8 and tube It and the wires 28 are preferably provided with a small amount of glass fused thereon, which insures an air-tight joint between the wires 28 and themejeting ends of the tube It and cap i'ifwhen these parts are fused together. The caps and tube N form an airtight tubular structure.

2sIn operation, the thermionic electrodes 23 and sufficiently to emit electrons, after which the .series connection is broken and the circuit is made through the conducting gas and mercury vapor between the electrodes. The mercury vapor becomes ionized and emits ultra-violet light which excites the fluorescent material II to emit a brilliant light.

In Figure 6, I have shown a slight modification of the invention wherein the wires 29 are attached to the supporting wires 21 and passed through the outer end of the tubular nipple 20 and hence to the exterior of the tube It. This dispenses with the necessity of passing the wires 28 through the periphery of the tube l0. All other parts of the lamp are identical with those shown and described in connection with Figures 1 to 5 in clusive. s.

In Figures 7 to 11 inclusive, the numeral 39 designates a preferably cylindrical outer tube formed of glass or the like and having its inner are first connected in series and are heated zcntal wire portions 45 fitted upon the end of the tube 39 adjacent to the cap 48 and is secured upon the tube by Bakelite cement or the like.

The insulating 84, having electrical connection with the wires 59, connected with the wires 52. Terminal-plugs 56 are also carried by the insulating cap 53 and are connected with wires 51, arranged exteriorly of the tube 39 and extend longitudinally thereof and are connected with the rigid horizontal wire portions 45. The wires 31 are preferably covered with insulating material. These wires pass through an opening lil formed in a bead 59 upon the cap 53.

In assembling the various parts of the lamp, the unit including the thermionic electrode 43 is first introduced into the tube 39 and the horithe openings 47 and fused therein. The thermionic electrode BI is first mountedupon the stem 49 andth'e electrode BI and cap 48 as a unit is applied to the open end of the tube 39. The

cap 43 is then fused to thistube. The air is exhausted from the tube 39 and the mercury and/or rare gas is. then introduced into the tube 39. The wires 55 are passed through the tubular terminal-plugs 54 and the wires 51 are passed through the tubular terminal-plugs 56, and the insulating cap is applied to the tube 39, after which the several wires are soldered to the terminal-plugs as described in connection with the surface coated with a fluorescent material 40,

is adapted" to be introduced into the tube 39 I through its opposite end, by a suitable instrument, and the horizontal wire portions 45 are passed outwardly through openings 41 formed in the tube 39 and these horizontal wire portions are fused in these openings 4'! to form air-tight joints.

The opposite end of the tube 39 with respect to the closed end 42 is open and is covered by a glass cap 48, corresponding to the cap l3, Figure 2. The cap 48 is arranged in end-tc-end relation with the tube 39 and is fused thereto. The cap 48 carries a tubular stem 49 having the usual means to permit of the exhausting of air and the introduction of mercury and/or a rare gas such as neon, helium, zenon, krypton or argon. 50 designates a globule of mercury. The numeral 5| designates a thermionic electrode carried by rigid wires 52, which are embedded in the tubular stem".

The numeral 53 designates an insulating cap formed of "Bakelite or the like and this cap is trode carried by the tubular nipple and passing that end of the main tube first form of the invention.

It is to be understood that the forms of my invention herewith shown and described are to be taken. as preferred examples of the same and that various changes in the shape, size, and arrangement of parts may be resorted to without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, what I claim is:

1. In a fluorescent lamp, a main tube which is gas tight and has its inner surface coated with fluorescent material and contains a gaseous atmosphere, said main tube being provided at one end' with an internal tubular nipple, a thermi= onic electrode arranged within the main tube near one end thereof and mounted upon the tubular nipple, a second thermionic electrode mounted within the main tube near its opposite end, an insulating cap directly mounted upon adjacent to the tubular nipple, pairs of terminals mounted upon the insulating cap, a pair of wires connected with the opposite terminals of the thermionic electhrcugh 'the tubular nipple and connected with one pair of terminals carried by the insulating cap, and a pair of wires connected with the terminals of the other thermionic electrode and extending to the exterior of the main tube, the outer exposed portions of the last named pair of wires being insulated, the last. n'amed pai'rrof wires ex- "tending longitudinally of the main tube and i named pair'of wires being free from att chment '70 passing, between the adjacent outer and inner faces of the main tube and insulating cap to be held thereby and leading to the other pair of tarminals carried by the insulating cap, the last with the nipple.

2. In a fluorescent lamp, a main tube which is gas tight and has its inner surface coated with fluorescent material and contains a gaseous atmosphere, said main "tuba being provided at one end with an internal tubular nipple. a thermionic cap 53 carries terminal-plugs passed outwardly through aavaaeo electrode arranged within the main tube near one end thereof and mounted upon the tubular nipple, a second thermionic electrode mounted within the main tube near its opposite end, an

insulating cap mounted upon that end of the main tube adjacent to the tubular nipple, pairs of terminals mounted upon'the insulating cap, a pair of wires connected with the opposite terminals of the thermionic electrode carried by the tubular nipple and connected with one pair of terminals carried by the insulating cap, and a pair of wires connected with the terminals of the other thermionic electrode exterior of the main tube. the outer exposedportions 01' the last named pair of wires being 'arranged in substantial contacting relation with the outer surface of the main tube, the last named pair of wires extending longitudinally of the main tube exteriorly thereof and passing into the insulating cap and being free from attachment with the tubular nipple and leading to the other pair of terminals carried by the insulating cap.

3. In a fluorescent lamp, a main tube which is gas tight and has its inner surface coated with fluorescent material and contains a gaseous atmosphere, said main tube being provided at its and extending to. the r v 3 opposite ends with tubular nipples, a thermionic electrode arranged within the main tube near one end thereof and mounted upon the tubular nipple adjacent to such end, an insulating cap mounted upon that end of the main tube adjacent to said thermionic electrode, pairs of terminals mounted upon the insulating cap, a thermionic electrode arranged within the main tube near its opposite end and mounted upon the other tubular nipple, an insulating cap mounted upon the main tube adjacent to the last I named thermionic electrode, a pair of wires connected with the terminals of the first named thermionic electrode and connected with one pair of terminals carried by the first named insulating cap, a, pair of wires connected with the terminals of the second named thermionic elec- I trode and passing to the exterior of the main tube near the second named thermionic electrode, theexposed outer portions of the second named pair of wires passing between the insulating caps and the main tube, the second named pair of wires being connected with the other pair of terminals carried by the first named insulating cap.

ALFRED HOPKIN. JR. 

